diff --git a/requirements_dev.txt b/requirements_dev.txt
index cfcae85..754c721 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -3,10 +3,10 @@ bumpversion==0.5.3
 wheel==0.31.1
 watchdog==0.8.3
 flake8==3.5.0
-tox==3.1.3
+tox==3.2.1
 coverage==4.5.1
-Sphinx==1.7.6
-cryptography==2.3
+Sphinx==1.7.7
+cryptography==2.3.1
 PyYAML==3.13
 twine==1.11.0